TBHQ (tert-butylhydroquinone, C.sub.10 H.sub.14 O.sub.2, molecular weight 166.22, CAS No.1948-33-0) is a white to light tan crystalline solid phenolic antioxidant. Other major commercial phenolic antioxidants include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and propyl gallate. TBHQ is approved in the United States for food use up to 200 mg/kg of fat or oil in the food (21 CFR 172.185). TBHQ primarily functions as a food antioxidant by inhibiting fatty acid oxidation. Such oxidation leads to the production of objectionable end products such as peroxides, aldehydes and ketones that impart offensive odor and taste to the food.
TBHQ has other uses as well. TBHQ is approved for use in cosmetics up to 0.1% of the product and as an inhibitor of polymerization of polyunsaturated polyesters including those in contact with food (Comestics Ingredients Review, 1986).
In W. Stone, et al., J. National Cancer Inst., 89: 1006-1014, 1997, phenolic antioxidants have been reported as possibly reducing the risk of some forms of cancer, especially of the digestive system. However, high levels of BHA are suspected to cause forestomach carcinomas in rodents and high levels of BHT are suspected to cause liver cancers. TBHQ has exhibited no such carcinogenicity. Thus, a study to determine whether TBHQ reduces the risk of colon cancer was initiated. The results of this study prompted the discovery of the present invention, which has major health implications.